1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and apparatus for transmitting and receiving control information using an Identification (ID) that identifies a connection.
2. Description of the Related Art
To satisfy increasing demands for large-capacity data services such as various multimedia Internet services as well as voice services in the wireless communication market, active research has been conducted on new wireless transmission standards, such as Institute of Electrical and Electronics Engineers (IEEE) 802.16e Wireless Broadband (WiBro) or Mobile Worldwide interoperability for Microwave Access (WiMAX), Wireless Local Area Network (WLAN), and 3rd Generation Partnership Project Long Term Evolution (3GPP LTE).
In a wireless communication system, data and control messages are exchanged through one or more connections or flows on an uplink directed from a Mobile Station (MS) to a Base Station (BS) and on a downlink directed from the BS to the MS. The uplink and downlink connections are identified by their independent IDs.
FIG. 1 illustrates Connection IDs (CIDs) used to identify connections in a Mobile WiMAX system according to the related art.
Referring to FIG. 1, a CID space 100 is divided into a DownLink (DL) CID space 102 and an UpLink (UL) CID space 104. Each of the DL and UL CID spaces 102 and 104 includes predetermined CIDs of 16 bits, for example. Once a DL connection is established, a DL CID is selected from the DL CID space 102 and allocated to the DL connection. Similarly, if a UL connection is established, a UL CID is selected from the UL CID space 104 and allocated to the UL connection. Accordingly, the DL and UL CIDs do not have the same value.
FIG. 2 illustrates flow IDs used to identify connections in an Advanced Mobile WiMAX system according to the related art.
Referring to FIG. 2, a DL or UL flow ID 202 is selected from a whole flow ID space 200. Although flow IDs function like CIDs illustrated in FIG. 1, UL and DL flow IDs may have the same value.
A transmitter and a receiver may support Automatic Repeat reQuest (ARQ) to correct transmission and reception errors in data. An ARQ operation may be performed independently within each connection between the transmitter and receiver. Since packets for each connection are transmitted with a unique CID, the receiver can identify an initial transmission packet and a retransmission packet of the same connection by the CID of the connection and then combine the packets.
The transmitter and receiver may perform an ARQ reset on the uplink or the downlink due to ARQ synchronization loss or other implementation factors. In this case, if one of the transmitter and the receiver performs an ARQ reset, the other party cannot determine whether the ARQ reset is for an uplink or downlink data connection using only a flow ID set in an ARQ reset control message. Similarly, when control information for a connection which should be identified as an uplink or downlink connection is to be transmitted, it is necessary to indicate the link type of the connection.